Only one I remember in from the Camber era is one in a bedroom that I think eventually became the library annex. I have a vague recollection of it being the bedroom of one of the regents at some point, so requiring much cloak and daggery, but I haven't read the Camber era books for longer than I care to admit, so I could be wrong.

I checked. The portal I was originally thinking of, in a garderobe in a cellar, was in Valoret. There's a mention of it in King Javan's Year when they're talking about where to put their new portal, and they say that it was blocked (either way, it's in the wrong city). And that's when they put in the portal by the library and Javan assigns the chamber it's in to his secret Deryni advisers.

Yet there seems to be no mention of one in Corwyn. I have been skimming and re-reading ITKS and CM, and there are certainly some interesting aspects. Old Vivienne was extremely concerned about Kenneth Morgan marrying Alyce, because she sees this as 'diluting' one of the only full Deryni duchies. There are mentions of Stevana de Corwyn of course, and also Grania (much better name for the next Morgan daughter!) and of course Duke Stiofan was good friends with Lewys Ap Norfal. (Look up the Codex entry on the Green Tower too). So why wouldn't there be a portal in Coroth with that history? *sigh* Another question for KK in Chat?

If I could posit an answer, Alkari, it would be along these lines:

Lewys Ap Norfal performs his much-dreaded experiment and vanishes, triggering a major reaction from the Camberian Council. There is much effort toward concealing what he was trying to do, and even his daughter is forcibly married to Sief MacAthan, a member of the Council. Also during this period, Duke Stiofan dies without male issue, and punitive restraints are maintained on the Deryni titleholders (recall the increased age of majority was 25 for Ahern De Corwyn). The climate for Deryni was so bad that Stevana and Keryell arrange to secretly pass off one of their twin daughters (Vera) as the daughter of the human Laurela Howard. Since most people are familiar with the limitations of regular travel, use of a Transfer Portal would draw further scrutiny from hostile forces.

Legally, there is no new Duke of Corwyn until Alaric Morgan is born, and his parents aren't likely to use a Portal, even if they knew of it. His Deryni mother dies when he's still a child (in service to her king, effectively), and his human father lacks both the arcane ability and the free time to acquire such knowledge. Alaric Morgan's own training is mostly in secret from Vera in Cassan, and is much attenuated until after his marriage years later. Add the further not-uneventful passage of time, and Alaric Morgan is effectively without a Portal of his own.

Given the Lewys ap Norfal coverup, the paucity of male heirs, the increased scrutiny of the De Corwyns as known Deryni, and the alarums and excursions of Alaric's life, it is easy to see how a Portal in Coroth could've been destroyed or sealed off. Deryni Magic notes that Portals can fade from lack of use, and a user must know each Portal's unique signature before using it. So either there is no Portal in Castle Coroth at all, or there is one that is physically inaccessible and faded from lack of use, the signature being long since forgotten.

Given the Lewys ap Norfal coverup, the paucity of male heirs, the increased scrutiny of the De Corwyns as known Deryni, and the alarums and excursions of Alaric's life, it is easy to see how a Portal in Coroth could've been destroyed or sealed off. Deryni Magic notes that Portals can fade from lack of use, and a user must know each Portal's unique signature before using it. So either there is no Portal in Castle Coroth at all, or there is one that is physically inaccessible and faded from lack of use, the signature being long since forgotten.

I agree with your points as reasons for why the knowledge of a portal could have been lost, especially the one about fading through lack of use. Ahern lived in Castle Coroth for a while, but we don't know how much he used his magic and whether he knew anything about any portals there. And if Alaric himself lacks all the formal training that might enable him to find a lost portal (investigating the castle inch by inch, LOL), then he is going to need assistance to find it. Denis Arilan seems to have considerable portal expertise, though I am not sure if Morgan would want him crawling over his Castle!

I am wondering if / how much the other towers in Castle Coroth are used these days, after they had been sealed off by Duke Stiofan following Lewys ap Norfal's disastrous experiment. We are told in the Codex that only the Green Tower retains its coloured glass windows, and of course that is Alaric's own domain. I'd love to know about the other towers and whether they are used at all, and whether a portal is/was in one of them. Has Alaric ever gone and explored every inch of them, to see if there are even vague traces of a portal like the one we see at St Neot's in DC? Of course, with Stiofan himself being Deryni, any portal would likely be in the part of the castle he still used ... *sigh*.

One thing about those age limits: it seems that Brion managed to modify them and have Alaric assume his full role as Duke once he attained his majority, so he didn't have to wait until age 25. The age limit was set so that the Deryni had to "prove" their loyalty to the Crown, but it seems Brion decided that Morgan's actions in the war with the Marluk were more than sufficient to demonstrate this!

... Denis Arilan seems to have considerable portal expertise, though I am not sure if Morgan would want him crawling over his Castle!

Arilan is also a member of the Camberian Council, and that body seems to have regarded Alaric Morgan as either underpowered or dangerously renegade. The mistrust is a two-way street, so Arilan may not have been permitted to assist Morgan in the matter, even if they both had been so inclined—and that was not assured, at least in the early books. (Thinking of the reappearance of Colin of Fianna's flask, that mutual distrust lasted a long time.)

I am wondering if / how much the other towers in Castle Coroth are used these days, after they had been sealed off by Duke Stiofan following Lewys ap Norfal's disastrous experiment. We are told in the Codex that only the Green Tower retains its coloured glass windows, and of course that is Alaric's own domain. I'd love to know about the other towers and whether they are used at all, and whether a portal is/was in one of them. Has Alaric ever gone and explored every inch of them, to see if there are even vague traces of a portal like the one we see at St Neot's in DC? Of course, with Stiofan himself being Deryni, any portal would likely be in the part of the castle he still used ... *sigh*.

Again, I'll remind you that Alaric is less well-trained in arcana and otherwise occupied for much of the time. I'd have to reread the books, but I think one of the towers houses his council chamber. Also, one floor of each (the top one?) was likely set aside for troops at some point in its history.

One thing about those age limits: it seems that Brion managed to modify them and have Alaric assume his full role as Duke once he attained his majority, so he didn't have to wait until age 25. The age limit was set so that the Deryni had to "prove" their loyalty to the Crown, but it seems Brion decided that Morgan's actions in the war with the Marluk were more than sufficient to demonstrate this!

The original strictures denied Deryni the right to any property at all. Corwyn was not part of Gwynedd then, and its geographic position near Torenth (possibly in conjuction with its economic position regarding Southern Sea trade) ensured that it was annexed with somewhat more favourable terms. Donal speaks in ITKS as if he dared not ease the restriction in Ahern's case, despite Ahern's own service (and injury sustained therein). Recall that Donal was no absolute monarch and had to submit himself to punishment from the clergy.

I agree that Brion would feel able to change the law on Alaric's behalf in light of the campaign against the Marluk (no doubt KK will have Brion say as much in a future book). There seems to be a gradual easing of the strictures against Deryni as time goes on and the terrible events of the Interregnum recede into the past; Brion dares to do more than Donal did, and Kelson dares to do more than Brion did. It looks like another long arc of history bending toward justice, with Kelson reaching out and exerting himself to shorten the curve.

Let God rise up, let his enemies be scattered; let those who hate him flee before him.As smoke is driven away, so drive them away; as wax melts before the fire, let the wicked perish before God.(Psalm 68 vv1-2)